2026-04-10 to 2026-04-11, the >22m bracket skyrocketed from 3.75c to 94.9c, while the 18-20m bracket crashed from 60c to around 1.5c. This was driven by initial Friday box office numbers revealing a much stronger-than-expected weekend hold, locking the total above $22 million. 2026-04-09 to 2026-04-10, the 20-22m bracket surged from 16.5c to 55.5c, followed by wide fluctuations between 32.5c and 50c. This was driven by significant upward revisions in weekend box office tracking as the actual weekend approached, causing rapid repricing by traders. 2026-04-08 to 2026-04-09, multiple brackets experienced extreme volatility. The <18m bracket crashed from 40c to 9c, the 18-20m bracket dropped from 55c to 4c before rebounding to 38.5c, and the 20-22m bracket surged from 29.5c to 46c then fell to 16.5c. This was likely driven by frequent revisions in weekend box office estimates and large traders causing temporary pricing inefficiencies.

April 12, 2026 - April 13, 2026: The price of the 29°C option surged from 38.5c to 75.5c, while the 28°C option plummeted from 42.5c to 0.3c. This was driven by the actual daytime temperature rising rapidly and exceeding the 28°C threshold earlier than expected, prompting the market to eliminate 28°C as a possible outcome and shift all probability to 29°C and higher. April 11, 2026 - April 12, 2026: As the HKO firmly established the maximum temperature forecast for April 13 at 29°C, options for 30°C and above continued to plummet (e.g., 30°C dropped from 27c to 5.5c, and '31°C or higher' dropped from 6.5c to 0.7c). Meanwhile, the 28°C and 29°C options surged (28°C climbed from 23.5c to a peak of 49c, and 29°C rose from 30c to 43c). This was caused by the market pricing out higher-than-expected temperatures and concentrating capital on the most reasonable outcomes near the forecast's upper bound. April 10, 2026 - April 11, 2026: The price of the '31°C or higher' option plummeted from 29c to 5c, and the 30°C option also declined, while prices for 27°C, 28°C, and 29°C saw significant increases. This was driven by the HKO adjusting the April 13 forecast maximum down from 30°C to 29°C, prompting the market to rapidly revise its expectations for extreme heat. April 9, 2026 - April 10, 2026: The prices of multiple options at or below 27°C plummeted (e.g., 27°C dropped from 28.5c to 2.25c, and 26°C from 24c to 2c). This was driven by the updated 9-day forecast from the HKO, which confirmed a significant temperature rise due to a southerly airstream. Meanwhile, the '31°C or higher' option fluctuated heavily between 16.5c and 29c as the market continuously reassessed the likelihood of daytime heating breaking the 31°C threshold.

The title mentions 'Seoul,' but the rules explicitly state the resolution source is the Incheon Intl Airport Station. Given the geographical distance, temperature differences may occur. Users relying solely on downtown Seoul's weather data might be misled. Additionally, data resolves only to whole degrees Celsius.

April 12, 2026 - April 13, 2026, the price of '21°C' surged from 20.5c to 51c, while '20°C' dropped to 33.5c after hitting 50c, as real-time temperature data on the resolution day caused a reallocation of funds between the two most likely outcomes. April 11, 2026 - April 12, 2026, as weather forecasts became clearer, the prices of the '20°C' and '21°C' options climbed from around 15c and 11.5c to peaks of 28.5c and 29c respectively, reflecting increased market confidence. April 9, 2026 - April 12, 2026, extreme high-temperature options plummeted. '23°C or higher' crashed from 38.5c to around 8.7c as meteorological models reached a consensus.

There is a divergence. Public meteorological forecasts (like Wunderground) predict a high for April 13 at Incheon Airport between 66°F and 68°F (19°C to 20°C), yet the prediction market prices 21°C as the most likely outcome at 51c. This discrepancy may be due to actual intra-day temperatures exceeding earlier forecast models, or market participants acting on more real-time observation data from the airport station.

April 12, 2026 - April 13, 2026, the price of '19°C' surged from 35.5c to 57c, while '18°C' plummeted from 27.5c to 4.65c. This occurred because, as the afternoon of April 13 approached in Beijing Time, real-time temperature observations increasingly locked the daily high around 19°C. April 9, 2026 - April 12, 2026, the price of '19°C' surged from 17.5c to 35.5c, and '18°C' rose from 15c to 27.5c, while '23°C or higher' plummeted from 24c to 1.45c. This is because approaching weather forecasts confirmed cooler temperatures (around 18-19°C with chances of rain), eliminating the possibility of extreme heat. April 9, 2026 - April 10, 2026, the price of '23°C or higher' plummeted from 24c to 6.5c. This is because, as the date approached, weather forecasts clearly indicated temperatures around 19°C, drastically reducing the likelihood of extreme heat.

While daily weather is widely monitored, betting on the exact integer high temperature for a specific city on a specific date falls outside standard daily concerns. It carries some novelty but remains a standard, albeit niche, category within prediction markets.

There is a significant divergence. The prediction market currently prices 16°C, 17°C, and 18°C significantly higher (highest Yes prices), whereas mainstream weather forecasts explicitly point to a maximum temperature around 14°C. The current market price distribution is irrational.